Intraocular lenses (IOLs) can be implanted in the anterior chamber, at the iris plane, in the ciliary suclus space, in the posterior chamber, in the capsular bag, or at other intended spaces inside the eye. Such lenses are used in a variety of surgical procedures such as cataract surgery, clear lensectomy/vision correction, secondary implantation of an intraocular lens, phakic intraocular lens, and other vision correcting procedures.
It is important that intraocular lenses are implanted with the correct orientation, in order for the lens optic to achieve the desired optical result and desired movement. Many intraocular lenses with advanced optical qualities, such as toric optics, require proper orientation and precise alignment to a predetermined ocular axis in order to achieve the intended visual results.
Misalignment can occur at the time of surgery and even after surgery, in the post-operative period due to rotational movements. Misalignment can adversely effect the visual result for the patient.
There are a number of intraocular lenses which are designed to move inside the eye, in order to provide additional optical benefits such as accommodation and enhanced voluntary focusing of vision. These intraocular lenses feature toric optical correction which require precise alignment. Misalignment of the toric correction can create optical problems.
There are also a growing number of multi-focal intraocular lenses which are designed to correct near and intermediate vision so that bifocal or trifocal glasses are not needed. These multi-focal lenses, which can correct astigmatism, need to be aligned precisely with a pre-determined axis of the eye, as well. In the same vein, there are phakic intraocular lenses designed to correct astigmatism, which likewise need to be aligned precisely with a pre-determined axis of the eye, as well.
Currently, intraocular lens manufacturers address the issue of intraocular lens orientation by using design features such as clear round dots, clear lines, holes, notches, and tabs, to signal the proper orientation of the intraocular lens. However, these design features may be difficult to use for several reasons.
First, these design features are small and difficult to see, because they are designed to minimize visual interference with the functions of the eyes. Further, intraocular lenses are typically made out of highly transparent and colorless materials, making these subtle features even more difficult to discern. Further, when a lens is folded and rolled-up in the injector, these design features cannot be identified correctly. Likewise, when the lens is unfolded in an eye with a small pupil, it is frequently difficult or impossible to see the orientation dot, line, notch, hole or tab, because the mark may be hidden behind the iris. After the lens has unfolded, if the iris covers and obscures either a clear or colored orientation mark, the obscured mark is rendered useless.
In U.S. Pat. Nos. 6,235,055 and 8,308,800, the present inventor discloses the use of a colored mark on the haptics of a toric IOL that helps to mark the axis of the IOL. These patents also suggest the use of bi-color marks to aid in the anterior and posterior orientation of the intraocular lenses.
The current IOLs also lack suitable marks indicating the magnitude for optical correction. Toric optical corrections have a magnitude known in diopters which can range from 0.25 to 6.0 diopters or greater. It would be useful to have a method of marking to reflect this information. Currently, there is not such method of marking.